The invention relates to a polymer material for manufacturing arcing chambers for low-voltage switchgear, as well as to a method for manufacturing the same.
In low-voltage switchgear, such as low-voltage power circuit-breakers, the switch-off arc is supposed to migrate from the point of origin, i.e., from the separating contacts, quickly into the quenching device, i.e., into the arc splitter plates. The properties of the material of the arc-quenching or arcing chamber have a considerable effect on this arcing movement, particularly in the case of short-circuit breaking. It happens, namely, during arcing movement that gaseous products are released from the chamber material because of the briefly occurring high arc temperature. These gases are needed to quickly extinguish the arc if they have the necessary chemical composition and when they are formed--per switching operation--in a quantity that is suited for avoiding too high a pressure inside the switch.
Under the state of the art, one has generally used molded materials based on cellulose-fiber-filled melamine-formaldehyde resins to fabricate arcing chambers (see, e.g.: Hansj urgen Saechtling "Kunststoff-Taschenbuch" [Plastics Manual], 24th edition, Carl Hanser Publishers, Munich 1989, p. 452). However, these are thermosetting materials, and--due to the long mold occupation time and the required postcure--it is, therefore, complicated and expensive to manufacture the chambers, even though this is done analogously to injection molding.
The object of the invention is to specify a polymer material that will make it possible to substantially shorten the cycle times required in the manufacturing of arcing chambers for low-voltage switchgear.